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1. Field of the Invention
The present invention relates generally to the art of window coverings, and more particularly to the types of window coverings which include a bottom rail, such as horizontal blinds, pleated blinds, cellular blinds, certain Roman shade products, light control window coverings and the like. In its most preferred form, the present invention relates to a system for adding weight to and/or balancing the bottom rail, so that it remains in a horizontal orientation when lowered and so that the front edge of the bottom rail and the rear edge of the bottom rail lie in an orientation desirable from an aesthetic and product utilization standpoint.
2. Description of the Prior Art
A wide variety of different types of window coverings are known which include a bottom rail. Familiar examples include horizontal venetian-type blinds, sometimes referred to as mini-blinds, although the slats may be quite large, pleated shade window coverings, cellular window coverings, various light control products and certain Roman shade products. Typically, such window coverings include a head rail to be mounted at the top of a window, window covering material coupled to or rolled up within the head rail and a bottom rail coupled to the lower end of the window covering material. With venetian-type blinds, a ladder system is employed to suspend a plurality of slats in a horizontal orientation between the head rail and bottom rail, and two or more lift cords are located between the ends of the slats and are passed through each slat from the bottom rail to the top rail. Typically the lift cord passes through holes in each slat, although other systems are known in the art. Most frequently, the lift cords are directed using pulleys or other mechanisms in the head rail to one end of the head rail, at which point they descend along one side edge of the window covering so that they can be manipulated by the user. By pulling on the lift cords, the bottom rail is moved toward the top rail, with corresponding accumulation of slats on the bottom rail as the upward movement continues.
Similar lift cord systems are used in a variety of the xe2x80x9csoftxe2x80x9d window products which are currently popular, including window coverings which have pleated fabric between the head rail and the bottom rail, window coverings which have cellular fabric material between the head rail and the bottom rail, light control products which include cells having opaque portions arranged between the bottom rail and a roller within the head rail, and the like.
Systems are also known wherein the lift cords may accumulate on spring motor reels within the head rail so that they do not exit the head rail at all. Such a system is shown in U.S. Pat. No. 5,482,100 issued Jan. 9, 1996 to Kuhar entitled xe2x80x9cCordless, Balanced Venetian Blind Or Shade With Consistent Variable Force Spring Motorxe2x80x9d. This system uses spring motors to balance the weight of the bottom rail and the accumulating window covering material as the window covering is raised or lowered by simply grasping the bottom rail and urging it upwardly or downwardly.
A problem common to such window coverings is balancing of the bottom rail and in some cases adding sufficient weight to the bottom rail to have it hang properly or lower smoothly. Due to various manufacturing considerations, such as the location and placement of the lift cords, the ways in which the ladders or window covering material are attached to the bottom rail, and the characteristics of the window covering material itself, there may be a need to provide weight in the bottom rail at various locations from end to end or various locations from front to back. Such problems are most pronounced in window coverings of the xe2x80x9csoftxe2x80x9d variety in which the head rail itself may be of a lighter gauge material due to the delicate nature of the window covering material.
Several solutions to the weight distribution problem have been proposed. The simplest is the use of weighted, tape-like strips which are adhered to the bottom rail by the fabricator at appropriate locations. Most frequently, such strips are applied after the window covering has been fabricated and after it has been determined where any imbalance may exist.
Another suggestion for resolving the weight balance issue is that proposed in U.S. Pat. No. 5,320,154 issued Jun. 14, 1994 to Colson, et al. and entitled xe2x80x9cMethod and Apparatus For Mounting A Retractable Window Coveringxe2x80x9d. In the disclosed device, a weight element is slidably disposed in the bottom rail and is moved longitudinally along the bottom rail until appropriate balance is achieved.
While both of these known systems provide control over the imbalance issues discussed above, they suffer from one or more drawbacks with regard to installation and/or use. For example, with fabric window coverings, the balance may change after the window covering has been used, for example if the pleats in cellular or pleated shades hang out for extended periods of time after initial manufacture. In such cases, it may be necessary to dismantle the bottom rail and readjust the weight and balancing system, a process which may be difficult when using a tape system or a sliding system, depending on the skill of the owner or user of the window covering.
A weight and balancing system which would be readily adaptable to a wide variety of window coverings and which would be easily understood and used by consumers would represent a significant advance in this art.
The present invention features a bottom rail weight and balancing system which is widely adaptable to different types of window coverings and which is inexpensive, easy to install and easy to adjust.
The present invention also features a bottom rail weight and balancing system which may be adjusted by an untrained consumer after a window covering has been installed.
A different feature of the present invention is to provide a weight and balancing system which may be used for a variety of sizes of window coverings and which may be manufactured in different configurations to permit different incremental adjustments to enhance the accuracy of the balance desired for aesthetic and operational purposes.
How these and other features of the present invention are accomplished will be described in the following detailed description of the preferred embodiment, taken with the FIGURES. Generally, however, they are accomplished by providing one or more body members which are inserted into the bottom rail and may be disposed along the bottom rail at a location selected by the individual responsible for weighting and/or balancing same. The body members include a plurality of sockets adapted to receive weights, the sockets being arranged from front to rear. Weights are inserted into selected ones of the sockets to accomplish the appropriate weighting and/or balancing. The features are accomplished in the most preferred form of the invention by using body members having a plurality of horse-shoe shaped sockets adapted to receive weights which are round in cross-section. The preferred weights are elongate rods which are snapped into the sockets. The number of rods used, and the particular sockets employed, are varied to accomplish the desired weighting and/or balancing objectives. The body members may also be used as part of the mechanism for attaching the window covering material to the bottom rail. Other ways in which the features of the invention are accomplished will become apparent to those skilled in the art after they have read the present specification. Such other ways are deemed to fall within the scope of the present invention if they fall within the scope of the claims which follow.